HAMAMATSU, SHIZUOKA PREF. – Thirteen public elementary schools in Hamamatsu, Shizuoka Prefecture, were closed as of noon Friday due to a suspected mass outbreak of food poisoning likely caused by norovirus, officials said.
The closures began Thursday after at least 905 pupils reported vomiting and diarrhea at 14 out of 104 public elementary schools in Hamamatsu, the local board of education said.
The outbreak prompted officials to order all local schools and kindergartens to stop serving lunches for four days starting Monday.
“Most of them developed such symptoms last night. They had eaten school lunches, but any causal relation with the symptoms has yet to be confirmed,” said Seiko Terada, the board of education’s director of health and school lunches.
About 40 teachers and staff at the 13 schools also showed symptoms of food poisoning, the board said, but none of the pupils or teachers required hospitalization.
According to the board of education and local public health officials, norovirus was detected in 11 out of 17 stool samples taken from the sickened pupils.
“It’s a very unusual situation where there are so many absentees,” Terada said. “We haven’t seen such a level before.”
Terada said that most of the affected pupils developed their symptoms Wednesday night after eating lunch at school earlier in the day.
The local health center began inspecting the school kitchens and serving utensils at the schools from Thursday after learning of the unusually high absentee rate. Six schools had been checked as of Thursday.
Health officials also planned to perform stool tests at schools where at least 40 pupils were affected.
About 60 percent of the pupils who were absent Thursday live in Higashi Ward, with 96 of them attending 376-pupil Nakanomachi Elementary School in the ward.
Nakanomachi was among the 12 schools that were closed Thursday.
“We were flooded by phone calls the whole morning, and I thought this was a big deal,” said Yutaka Mabuchi, principal at one of schools that was inspected Friday. “We are checking the course of the kids’ symptoms.”
Meanwhile, the public health center instructed elementary and junior high schools to disinfect their facilities using bleach containing sodium hypochlorite, which is believed to be a highly efficient disinfectant.
Health officials also recommended people thoroughly wash their hands with soap and water.